Quality assessment

The systematic review includes substantial literature on the effect of community engagement on child outcomes. However, the review has some major limitations. The study inclusion criteria and any methods used to reduce bias in study screening and data extraction are not clear. There is no search for grey literature. Moreover, the characteristics and results of the included studies are not clearly reported and the approach to analysis is not entirely clear, nor justified. For example, the authors use a descriptive synthesis method without explaining the reason or possibility of synthesizing the effect sizes for the 16 RCTs included. In exploring heterogeneity different common themes were identified for similar studies however it is not clear what the basis of these themes are. Finally, there is no clear reporting of risk of bias for each study, or consideration of risk of bias across all studies. Considering what appears to be very broad study design inclusion criteria and overall lack of transparency this is a particular concern.